Ulrich Disko

Intact phospholipids—microbial “life markers” in marine deep subsurface sediments

AbstractDeepsubsurfacesedimentsfromtheNankaiTrough,JapanSea,ODPLeg190,sites1173,1174,1177,andnear-surfacesedimentsfromHydrateRidge,NE-Pacifichavebeenanalysedbyhighperformanceliquidchromatography(HPLC)–electrosprayionisation(ESI)-massspectrometry(MS).Themainobjectivewastoutilizethepresenceofintactphospholipidsasadirectindicatorofviablemicroorganisms.TheextractsofNankaiTroughsedimentswerefoundtocontainavarietyofphospholipid(PL)structures,well-knowntostemfrommicroorganisms,todepthsasgreatas745mbsfandinsitutemperaturesashighas85C.Inaddition,highrelativeamountsoflysophospholipids(e.g.lysopho-sphatidylcholines)exceedingthoseoftheregularphospholipidsweredetected.DiglyceridemassfragmentsofvariousPLshavebeenassignedtofattyacylside-chainsoftypicalchainlength(C 14 ,C 16 ,C 18 ,C 20 )anddegreeofunsaturation(zero,oneortwodoublebonds).Similarresultswereobtainedforthephospholipiddistributioninextractsoforganicmatter-richHydrateRidgesediments.Todate,theenhancedoccurrenceoflysophospholipidscannotbeexplainedcompletelybutaresponsetoincreasingthermalandecologicalstressseemsprobable.# 2003ElsevierScienceLtd.Allrightsreserved.1.IntroductionBiologicalmarkersprovideinformationonthepre-cursorbiotaandpost-depositionalhistoryoforganicmatterpreservedinsediments,therebyenablingbiolo-gicalevolution,palaeoclimateandpetroleum-formingprocessestobedocumentedindetail(Brassell,1993;PetersandMoldowan,1993).Thisinformation,whetherbasedonhydrocarbonsorfunctionalisedcompounds,haslargelybeengatheredusinggaschromatography-massspectrometry,andwasinitiallymadepossiblebyrapidtechnicaladvancesinthemid-1960s.Inthelatterpartofthelastcentury,anewandcompellingchallengebegantotakeshape,thisbeingtodefinethetempera-ture-anddepthlimitstowhichlifecanoccurwithintheEarth.Thiswasmotivatedbythediscoveryofmicro-bially-basedecosystemsfuelledbygeothermalenergyathydrothermalvents,andtheoccurrenceofdiversemicrobialpopulationstohundredsofmetresdepthinclasticsediments(Craggetal.,1992;Parkesetal.,1994,2000;FredricksonandOnstott,1996;Wellsburyetal.,1997;Boetiusetal.,2000).Carbonatemoundswhoseformationmaybeinitiatedbymethanotrophicbacteria,gashydrates,andbiodegradedpetroleumreservoirsalsobearwitnesstothefactthatthisso-calleddeepbio-spheremaybeubiquitousandinterceptfluxesfromthegeosphere.Bacterialcommunitiesinsubsurfaceenvironmentsaremostcommonlyquantifiedbycellcounting(Cragget

Chlordecone fate and mineralisation in a tropical soil (andosol) microcosm under aerobic conditions.

Chlordecone is a persistent organochlorine insecticide that, even decades after its ban, poses a threat to the environment and human health. Nevertheless, its environmental fate in soils has scarcely been investigated, and elementary data on its degradation and behaviour in soil are lacking. The mineralisation and sorption of chlordecone and the formation of possible metabolites were evaluated in a tropical agricultural andosol. Soil microcosms with two different soil horizons (S-A and S-B) were incubated for 215 days with 14C-chlordecone. At five different times (1, 33, 88, 150 and 215 days) the extractability of 14C-chlordecone was analysed. Mineralisation was monitored using 14CO2 traps of NaOH. The appearance of metabolites was studied using thin layer and gas chromatography techniques. At the end of the experiment, the water soluble 14C-activity was 2% of the remaining 14C-chlordecone for S-A and 8% for S-B. Only 12% of the remaining activity was non extractable and more than 80% remained extractable with organic solvents. For the first time to our knowledge, a significant mineralisation of chlordecone was measured in a microcosm under aerobic conditions (4.9% for S-A and 3.2% for S-B of the initial 14C-activity). The drastically lower emission of 14CO2 in sterilised microcosms indicated the biological origin of chlordecone mineralisation in the non-sterilised microcosms. No metabolites could be detected in the soil extracts. The mineralisation rate of chlordecone decreased by one order of magnitude throughout the incubation period. Thus, the chlordecone content in the soil remained large. This study confirms the existence of chlordecone degrading organisms in a tropical andosol. The reasons why their activity is restricted should be elucidated to allow the development of bioremediation approaches. Possible reasons are a heterogeneous distribution a chlordecone between sub-compartments with different microbial activities or a degradation of chlordecone by co-metabolic processes controlled by a limited supply of nutrients.

Molecular measurements of maturity for Lias δ shales in N.W. Germany

Abstract The extractable aliphatic and aromatic hydrocarbons of twenty-four Lias δ shales from N.W. Germany have been analysed by gas chromatography-mass spectrometry. Particular attention has been paid to seven molecular measurements of thermal maturation which are based on appropriate ratios of the concentrations and products of certain reactions. A sequence of increasing maturity towards the area of the Bramscher Massiv was determined. Because the reactions involved occur at different rates, they reach completion at different levels of maturity and at variable distance from the centre of the Bramscher Massiv, as defined by iso-vitrinite reflectance contours reported previously for Rhaetic, Lias and Malm shales. This has allowed the designation of zones of increasing maturity. The molecular measurements appear more reliable assessors of maturity than vitrinite reflectance for samples less mature than the zone of oil generation, but are not applicable to samples from within this zone, because the reactions concerned have normally reached completion. A mathematical model suggests that the maturity of samples less mature than a vitrinite reflectance of 1%, can adequately be explained by substantial subsidence during Early and Middle Cretaceous followed by major uplift and inversion in Late Cretaceous time, without recourse to further heating from a deep seated igneous intrusion.

Fluoren-9-ones and carbazoles in the Posidonia Shale, Hils Syncline, northwest Germany

The distribution of alkylated fluoren-9-ones and carbazoles, including their benzo- and dibenzo- and/or naphtho-annellated derivatives, have been investigated in rock extracts from a maturity sequence of Posidonia Shales from the Hils Syncline of northwest Germany. The fluoren-9-one and carbazole derivatives are quantitatively the most important compound types in the low polar heterocompound fraction obtained from the Posidonia Shale bitumens by liquid chromatography. This fraction comprises 9.3–27.5% of the total bitumen depending on maturity. The concentration of the fluoren-9-ones in the bitumens systematically increases with increasing maturity. Generally, a trend of decreasing degree of alkylation is observed with increasing maturity. However, at the molecular level, less systematic maturity-dependent variations are observed for the fluoren-9-one distribution than for the carbazole distributions. A remarkable exception is the 1-ethylfluoren-9-one(1-ethylfluoren-9-one + 1,8-dimethylfluoren-9-one) ratio which linearly decreases over the entire maturity range (0.48–1.45% Rr). Among the carbazoles, dibenzo-and/or naphtho-annellated derivatives become more abundant at higher maturity. An oxidation of fluorenes may be ruled out as the major process for the formation of fluoren-9-ones since Posidonia Shale was deposited under anoxic conditions and fluorenes are not present in high amounts even in samples of low maturity. The fluoren-9-ones may rather be produced by cyclisation reactions of suitable precursors in the organic matter. Particularly, 2-carboxybiphenyls could be transformed to fluoren-9-ones either catalysed by Lewis acids, e.g. clay minerals, or solely under the influence of higher temperatures. The constant ratio of fluoren-9-ones and benzofluoren-9-ones suggests that selective formation/degradation and interconversion during maturation plays a minor role. this seems to be different for the carbazoles where a significant influence of maturity on the distribution of derivatives with different numbers of aromatic rings was observed.

Determination of hydrocarbon distributions in oils and sediment extracts by gas chromatography—high resolution mass spectrometry

Abstract The distributions of steroid and triterpenoid hydrocarbons in crude oils and sedimentary rock extracts can be routinely determined by the direct injection of the sample into a gas chromatograph coupled to a mass spectrometer (GC-MS). The mass spectrometer is operated at a resolution of about 2500 (10% valley), and only the ion intensities at selected accurate mass values, diagnostic of the structural types of interest, are monitored throughout the analysis. The distributions, so obtained, find application in the assessment of the source and thermal maturity of crude oil accumulations in the subsurface. This technique eliminates chromatographic separation steps and combines two analyses in one. Thus, more geological samples and reference mixtures may be analyzed in a given time.

Aromatic aldehydes and ketones in the Posidonia Shale, Hils Syncline, Germany

Abstract The low-polarity NSO compound fraction of Posidonia Shale bitumens has previously been shown to contain fluoren-9-ones and benzofluoren-9-ones as the quantitatively most abundant compound class. The present study, based on detailed gas chromatography-mass spectrometry describes the distribution of naphthaldehydes, alkylnaphthylketones, benzaldehydes, alkylphenylketones, 1-indanones and 1-tetralones as additional types of aromatic carbonyl compounds in these samples. Benzene-derived carbonyl compounds are less abundant than the other identified compound classes. The observed distributions show some remarkable maturity related variations. Particularly, the ratios of α- and β-isomers of naphthalene-derived carbonyl compounds behave in a similar manner to the corresponding hydrocarbons, i.e. they show a relative increase of the β-isomers with increasing maturity. The 1-indanone/(1-indanone + 1-tetralone) ratio (ITR) is suggested as a new heterocompound based maturity parameter. The carbonyl compounds described may be derived either from inter- and/or intramolecular acylation and formylation reactions or from oxidation of benzylic methylene groups of alkylated aromatic hydrocarbons.

Benzoxazolinone detoxification by N-Glucosylation: The multi-compartment-network of Zea mays L.

ABSTRACT The major detoxification product in maize roots after 24 h benzoxazolin-2(3H)-one (BOA) exposure was identified as glucoside carbamate resulting from rearrangement of BOA-N-glucoside, but the pathway of N-glucosylation, enzymes involved and the site of synthesis were previously unknown. Assaying whole cell proteins revealed the necessity of H2O2 and Fe2+ ions for glucoside carbamate production. Peroxidase produced BOA radicals are apparently formed within the extraplastic space of the young maize root. Radicals seem to be the preferred substrate for N-glucosylation, either by direct reaction with glucose or, more likely, the N-glucoside is released by glucanase/glucosidase catalyzed hydrolysis from cell wall components harboring fixed BOA. The processes are accompanied by alterations of cell wall polymers. Glucoside carbamate accumulation could be suppressed by the oxireductase inhibitor 2-bromo-4´-nitroacetophenone and by peroxidase inhibitor 2,3-butanedione. Alternatively, activated BOA molecules with an open heterocycle may be produced by microorganisms (e.g., endophyte Fusarium verticillioides) and channeled for enzymatic N-glucosylation. Experiments with transgenic Arabidopsis lines indicate a role of maize glucosyltransferase BX9 in BOA-N-glycosylation. Western blots with BX9 antibody demonstrate the presence of BX9 in the extraplastic space. Proteomic analyses verified a high BOA responsiveness of multiple peroxidases in the apoplast/cell wall. BOA incubations led to shifting, altered abundances and identities of the apoplast and cell wall located peroxidases, glucanases, glucosidases and glutathione transferases (GSTs). GSTs could function as glucoside carbamate transporters. The highly complex, compartment spanning and redox-regulated glucoside carbamate pathway seems to be mainly realized in Poaceae. In maize, carbamate production is independent from benzoxazinone synthesis.

6-Hydroxy-5-nitrobenzo[d]oxazol-2(3H)-one - A Degradable Derivative of Natural 6-Hydroxybenzoxazolin-2(3H)-one produced by Pantoea ananatis.

ABSTRACT Pantoea ananatis is a bacterium associated with other microorganisms on Abutilon theophrasti Medik. roots. It converts 6-hydroxybenzoxazolin-2(3H)-one (BOA-6-OH), a hydroxylated derivative of the allelochemical benzoxazolin-2(3H)-one, into 6-hydroxy-5-nitrobenzo[d]oxazol-2(3H)-one. The compound was identified by NMR and mass spectrometric methods. In vitro synthesis succeeded with Pantoea protein, with isolated proteins from the Abutilon root surface or with horseradish peroxidase in the presence of nitrite and H2O2. Nitro-BOA-6-OH is completely degraded further by Pantoea ananatis and Abutilon root surface proteins. Under laboratory conditions, 6-hydroxy-5-nitrobenzo[d]oxazol-2(3H)-one inhibits Lepidium sativum seedling growth whereas Abutilon theophrasti is much less affected. Although biodegradable, an agricultural use of 6-hydroxy-5-nitrobenzo[d]oxazol-2(3H)-one is undesirable because of the high toxicity of nitro aromatic compounds to mammals.

OrganoCat pretreatment of perennial plants: Synergies between a biogenic fractionation and valuable feedstocks

A successful biorefinery needs to align suitable pretreatment with sustainable production of biomasses. Herein, four perennial plants, (Sida, Silphium, Miscanthus and Szarvasi) regarded as promising feedstocks for biorefineries were subjected to the OrganoCat pretreatment. The technology was successfully applied to the different perennial plants revealing that pretreatment of grasses was more efficient than of non-grasses. Thorough analyses of the lignocellulose - before and after fractionation - enabled a detailed description of the fate of cellulosic, non-cellulosic polysaccharides and lignin during the pretreatment. Especially Szarvasi pulp displayed outstanding results in terms of fractionation efficiency and enzymatic digestibility, though in all cases successful lignocellulose fractionation was observed. These insights into the structural composition of different perennial plant species and the impact of the OrganoCat pretreatment on the plant material leads to useful information to strategically adapt such processes to the individual lignocellulosic material aiming for a full valorisation.

Interspecies-cooperations of abutilon theophrasti with root colonizing microorganisms disarm BOA-OH allelochemicals

ABSTRACT A facultative, microbial micro-community colonizing roots of Abutilon theophrasti Medik. supports the plant in detoxifying hydroxylated benzoxazolinones. The root micro-community is composed of several fungi and bacteria with Actinomucor elegans as a dominant species. The yeast Papiliotrema baii and the bacterium Pantoea ananatis are actively involved in the detoxification of hydroxylated benzoxazolinones by generating H2O2. At the root surface, laccases, peroxidases and polyphenol oxidases cooperate for initiating polymerization reactions, whereby enzyme combinations seem to differ depending on the hydroxylation position of BOA-OHs. A glucosyltransferase, able to glucosylate the natural benzoxazolinone detoxification intermediates BOA-5- and BOA-6-OH, is thought to reduce oxidative overshoots by damping BOA-OH induced H2O2 generation. Due to this detoxification network, growth of Abutilon theophrasti seedlings is not suppressed by BOA-OHs. Polymer coats have no negative influence. Alternatively, quickly degradable 6-hydroxy-5-nitrobenzo[d]oxazol-2(3H)-one can be produced by the micro-community member Pantoea ananatis at the root surfaces. The results indicate that Abutilon theophrasti has evolved an efficient strategy by recruiting soil microorganisms with special abilities for different detoxification reactions which are variable and may be triggered by the allelochemical´s structure and by environmental conditions.